This invention generally relates to printer apparatus and methods and more particularly relates to a compact printer with quick-loading cassette and method therefor, wherein the printer forms an image on a receiver sheet fed from the cassette and thereafter removes any curl present in the receiver sheet.
It is known that a typical thermal resistive printer includes a thermal resistive printhead capable of printing an image on a receiver medium, which may be cut sheets of paper or transparency. The receiver sheets are fed to the printhead by appropriate means and brought into contact with a dye donor ribbon. The printhead heat activates the dye donor ribbon to transfer dye to the receiver sheets in order to print an output image on the receiver sheets.
The possibility exists, however, that a user of the printer will inadvertently touch the dye donor ribbon when loading the dye donor ribbon into the printer. Touching the dye donor ribbon may damage the donor ribbon, such as by particulate matter and finger prints being deposited onto the donor ribbon. Of course, damage to the donor ribbon results in unacceptable artifacts appearing on the finished prints. In addition, the damaged donor ribbon may in turn damage the printhead. It is therefore desirable to avoid damaging the dye donor ribbon.
In addition, prior art printers necessarily require the donor ribbon and receiver medium be separately loaded into the printer. Separately loading the donor ribbon and receiver medium increases the time required to prepare the printer for producing prints. Therefore, it would be desirable to avoid separate loading of the donor ribbon and receiver medium.
Moreover, some printers require sheets of receiver medium to be individually hand-fed into the printer. However, hand-feeding receiver sheets into the printer may cause fouling of the receiver sheets (i.e., particulate matter and finger prints being deposited on the receiver sheets). It is therefore desirable to avoid hand-feeding individual receiver sheets into the printer.
A known technique to avoid hand-feeding individual receiver sheets is to provide a receiver sheet supply tray which holds a stacked-supply of the receiver sheets and which allows each receiver sheet to be mechanically fed into the printer. In this regard, receiver sheets are held in the receiver sheet supply tray, which is at least partially insertable into the printer, and mechanically supplied to the printhead housed in the printer. That is, a "picker" mechanism disposed in the printer engages the receiver sheets held in the supply tray and feeds individual receiver sheets to the printhead. Such a receiver sheet supply tray is of elongate rectangular shape to hold paper or transparency typically having dimensions of 8 inches wide by 11 inches long (i.e., "letter-size" sheets) or dimensions of 8.27 inches wide by 11.69 inches long (i.e., "A-4 size" sheets).
However, although use of the receiver sheet supply tray avoids hand-feeding individual receiver sheets, use of the supply tray is not entirely satisfactory where space conservation is a concern. That is, the elongate rectangular shape of the receiver supply tray results in a longer printer foot-print than would otherwise be the case because the length of the printer foot-print must accommodate the elongate shape of the receiver supply tray. It would therefore be desirable to reduce the size of the receiver supply tray in order to provide a compact printer while simultaneously accommodating "letter-size" or "A-4 size" receiver sheets.
One technique to reduce the size of the printer is to avoid use of an elongate receiver supply tray by providing a continuous roll of receiver tightly wound on a supply spindle mounted in a cassette, which is inserted into the printer. Use of the roll of receiver mounted in the cassette eliminates the need to use an elongate receiver supply tray and also may avoid fouling of the receiver. During the printing process, receiver continuously unwraps from about the receiver supply spindle to receive the image provided by the printhead. Sheets of the receiver are subsequently cut to size during the printing process to provide the desired print size, such as "letter-size" or "A-4 size" output.
Although use of a receiver roll reduces the printer exterior envelope by reducing its length, use the receiver roll can give rise to yet another problem. That is, use of the receiver roll can cause residual curl in the finished print, which is a highly undesirable result. Such residual curl is due to the receiver having been wound in a roll around the receiver supply spindle. Indeed, prints made from the receiver closest to the inner diameter of the receiver supply spindle exhibit the most curl in the finished print because the receiver is more tightly wound closest to the inner diameter of the receiver supply spindle.
Hence, prior art attempts to provide a compact printer and artifactfree prints by using a cassette-mounted roll of receiver rather than a receiver supply tray have resulted in finished prints with residual curl therein. Therefore, it would be desirable to provide a compact printer which does not produce curl in the finished print. It would also be desirable to avoid separate loading of the donor ribbon and receiver medium in order to save loading time.
Therefore, there has been a long-felt need to provide a compact printer with quick-loading cassette and method therefor, wherein the printer forms an image on a receiver sheet fed from the cassette and thereafter removes any curl present in the receiver sheet.